netdev - Re: [PATCH 6/6] fs: replace f_ops->get_poll_head with a static ->f_poll

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Message-ID: <CA+55aFxMGvgDavTjeLw77XSy0pCd=GBnzzryp3=vvsQNgyzcaw@mail.gmail.com>
Date:   Thu, 28 Jun 2018 14:16:04 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Al Viro <viro@...iv.linux.org.uk>
Cc:     Christoph Hellwig <hch@....de>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Network Development <netdev@...r.kernel.org>, LKP <lkp@...org>
Subject: Re: [PATCH 6/6] fs: replace f_ops->get_poll_head with a static
 ->f_poll_head pointer

On Thu, Jun 28, 2018 at 1:37 PM Al Viro <viro@...iv.linux.org.uk> wrote:
>
>
> Speaking of obvious bogosities (a lot more so than a blocking allocation
> several calls down into helper):
>
> static __poll_t ca8210_test_int_poll(
>         struct file *filp,
>         struct poll_table_struct *ptable
> )

Ok, that's just garbage.

Again, this is not an excuse for changing "->poll()". This is just a
bogus driver that does stupid things.

And again, don't use this as an example of "poll must not block" The
fact is, poll() *can* block for locking and other such things, and
it's perfectly normal and ok. It just shouldn't block for IO.

I will not take any misguided patches to try to "fix" poll functions
that might block.

But I will take patches to fix bugs in drivers. In this case, I think
the fix is to just remove that crazy "wait_event_interruptible()"
entirely.

Not that anybody cares, obviously. Apparently nobody has ever noticed
how broken that poll function is.

               Linus